Emma O'Neil was born on May 11, 1928, in Strem, Austria. In the early 1930s, she immigrated to the United States with her parents and brother. She grew up in New York City and, after marrying Thomas O'Neil in 1949, made her home on Long Island, where she lived for the remainder of her life.

Emma was the mother of seven children. One child died at birth, and she raised her remaining six children. Her youngest son, Matthew, was born with Down syndrome and required lifelong care and regular adult supervision.

A homemaker, Emma enjoyed gardening, reading mystery novels, watching classic films, and playing Rummikub.

Her Catholic faith remained an important part of her life. Emma was a parishioner of the Church of the Blessed Sacrament in Valley Stream for more than fifty years and attended Mass regularly until she was no longer physically able to do so. While living at Oceanside Care Center, she continued to participate by watching the daily televised Mass and received the Anointing of the Sick during her final illness.

Even in her final days, Emma continued to think about her family. She faithfully remembered birthdays, regularly sending cards over the years. Her final message to her family was simple:

"I love all my children."